Development of analytical protocols for chemical isolation of the target elements Li and B out of various sample types for their subsequent high-precision isotopic analysis using multi-collector ICP – mass spectrometry. Li (δ7Li) and B (δ11B) isotope ratios will be used as paleoproxies, i.e. to unravel information on the prevailing temperature, CO2 level, surface erosion levels, etc in the distant past.